Obstructive sleep apnea syndrome (OSAS) is a cessation of oronasal airflow caused by narrowed or collapsed upper airway.
The most commonly prescribed treatment for obstructive sleep apnea is to provide a continuous positive airway pressure during the sleep. A positive airway pressure device (PAP device) delivers air pressure through a nasal/oralnasal mask that the patient wears while sleeping. The pressure keeps the throat open for eliminating obstructive apneas and allowing the patient to breathe normally for whole night and to keep sleep uninterruptedly and restoratively.
One common type of PAP devices is CPAP device which provides a constant air delivery pressure. Other types of PAP devices are also available. For example, one is BiPAP (Bilevel PAP) device which provides two positive pressures, a lower pressure for the patient's expiration and a higher pressure for the inspiration. Another one is APAP (Auto PAP) device which automatically detects the patient's apnea/hypopnea and alters the air pressure according thereto. A further one is VPAP (Variable PAP) device which adjusts the air pressure in accordance with the patient's breathing pattern automatically.
All these developments are focused on adjusting the air pressure based on the patient's breathe, and thus, preventing improper air delivery pressure. Insufficient delivery pressure might be unable to open the airway, and excess delivery pressure might bring the patient uncomfortability, and also, cause mask leakage and/or arousal which on the contrary will influence the patient's sleep. Therefore, how to find out the minimum effective delivery pressure for the patient's most comfortability is one of the main goals in PAP development, and an example can be seen in U.S. Pat. No. 6,349,724.
However, as known, most PAP devices have a fixed hardware structure which limits the adaptation to the patient's different demands. Some improvements for this limitation are US 2007/0193583, which increases preloaded programs to provide multiple delivery modes, and US 2007/0023045, which provides the possibility to alter the hardware, and further, U.S. Pat. No. 6,397,845 and U.S. Pat. No. 7,204,250 provide the information about sleep stage according to the physiological signals for being the basis of air pressure adjustment.
The object of the present invention is to provide an air delivery system with hardware flexibility.
Another object of the present invention is to provide an air delivery system in which a PAP device can obtain additional functions through connecting with at least an external sensing device.
A further object of the present invention is to provide an air delivery system which employs an external and removable sensing device to provide signal inputs to the PAP device for adjusting the air delivery pressure to match the patient's real need.
Another further object of the present invention is to provide a multifunctional air delivery system in which the PAP device can cooperate with the external/removable sensing device or can operate independently.